[PATCH] Mantaining turnstile aligned to 128 bytes in i386 CPUs

John Polstra jdp at polstra.com
Tue Jan 16 20:34:29 UTC 2007


On 16-Jan-2007 Attilio Rao wrote:
> The patch:
> http://users.gufi.org/~rookie/works/patches/ts-sq/ts-sq.diff
> 
> The benchmark results:
> http://users.gufi.org/~rookie/works/patches/ts-sq/ts-sq.benchmark
> 
> The kernel options file:
> http://users.gufi.org/~rookie/works/patches/ts-sq/CURRENT

This is good stuff!  I tried your patch on a performance-critical
system that I've been working on.  Without going into a lot of detail,
it's a bunch of in-kernel code that blasts packets back and forth
between pairs of gigabit interfaces.  Userland isn't involved at
all.  Running 4 gigabit ports in this way on a Dell 1950 with 4 CPU
cores running at 3.0 GHz, I got about 4% better performance (in
terms of packets per second) using your patch.  That's a pretty good
improvement, considering that the design makes some effort to avoid
lock contention.

John


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